Several poly(arylene thioether)s (PTEs) containing a fluorene moiety were synthesized by the polycondensation of masked dithiols such as 9,9-bis(4-(N,N-dimethyl-S-carbamoyl)phenyl)fluorene and various difluoroarenes. All PTEs were obtained in quantitative yields. The PTEs showed good thermal stability: the 10% weight loss temperature was over 480 degrees C under both nitrogen and air atmosphere by TGA, and glass temperature was within a range of 204-275 degrees C by DSC. Most PTEs exhibited remarkably high refractive index values in a range of 1.66-1.72 at 589 nm, whereas they had a very low degree of birefringence properties. Furthermore, the PTEs showed high solubility in ordinary organic solvents such as chloroform, N-methylpyrrolidone, and tetrahydrofuran. (c) 2007 Wiley Periodicals, Inc.